There is a [list already on the freeframe site](http://community.freeframe.org/plugindatabase?pluginDB_ff_version=FFGL+1.5x&pluginDB_license=All&pluginDB_OS=All&pluginDB_type=All) but it isn't ever updated!

Plus there are the [plugins bundled with the Resolume demo](http://resolume.com/download/)

[Bigfugs plugins are here](http://www.bigfug.com/software/freeframe/)

[Here are some from 1210 visuals](http://www.1210visuals.net/index.php?option=com_content&view=article&id=51&Itemid=56)

[Various plugins free and commercial from the Mapio people](http://visution.com/downloads)